Carbureter.



A. P. BRUSH. OARBURETER.

APPLICATION FILED MAR. 21. 1912.

Patented Nov. 4, 1913.

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OARBURETER.

APPLICATION FILED MAR. 21. 1912.

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COLUMBIA PLANOGRAPH 470.. WASHINGTON, D. c.

more erases ALAINSON 1?. BRUSH, QB DETROIT, MICHIGAN.

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To all whom it may concern:

Be it known that I, ALANsoN P. BRUSH, a citizen of the United States, residing a Detroit, in the county of Wayne and State of Michigan, have invented a certain new and useful Improvement in Carbureters, of which the following is a full, clear, and exact description.

Carbureting devices for internal combos tron engines in automobile or like servloe therein produced by the induction strokes of the motor pistons. The vacuum must always be great enough toproduce an air flow of sufficient velocity to draw in a suitable quantity of fuel, and to break up and carry said fuel either in an atomized or vaporized condition to the motor. It is obvious, however, that this partial vacuum in the carbureter, however slight, must to some extent reduce the mass of mixture delivered to the cylinders, and, by so much, reduce the desired efiiciency of the motor. But, as stated, there must be some vacuum in the carbureter, or else no fuel would be drawn in. It therefore follows that this reduction in pres sure should be minimized in order to attain the highest practical efiiciency of the motor. If the opening through which the air enters a carbureter is of fixed size, the vacuum in the carbureter will rapidly increase as the throttle is opened for the purpose of pros ducing increased speed or power; and. two

undesirable results will follow, viz.,, the

velocity of the air stream will increase, and this will cause a disproportionately large, amount of fuel to be drawn in, thereby male ing the mixture too rich; also the mass of: mixture delivered to the cylinders will be reduced. It is because of these facts that auxiliary air valves are commonly provided n carb retors As these valves leave heir seats, the size of the openings through which the air enters the carburetor is increased,- and to that extent the part al at um con Specificaticnof Letters Patent. Application filed March 21, 1912. s ri rivo. 685,240."

inlet to the carbureter.

' connected b Patented Nov. 4-, i913.

ditions in the carburetor tend toward constancy. Also the mixture is diluted.

In the effort to maintain the uniformity of the mixture under the difierent working cond tions, various kinds of springs and combinations of springs have been employed to control the moveme'ntfof such auxiliary air valves; also differently shaped valves have been employed. While admitting the comparative excellence of 'some carbureters of the sort referred to, one may say without fear of contradiction that none of them are entirely satisfactory at all times. Other persons seeking the same end have proposed to vary, in different ways, the size of the fuel 7 But so far as I know, it has not before been proposed to utilize small reductions of pressure in the carbureter as the force whereby to open the auxiliary air valve so as to prevent any great reduction of vacuum, and to also open a fuel controlling valve so that the fuel drawn in will be properly proportioned to the air admitted notwithstanding the slight increase in vacuum, and to additionally employ a yielding resistant to check and control the opening movement of the fuel valve,-all with the result of producing a substantially uniform mixture at all times and with only a small increase in the partial vacuum conditions within the. carburetor. This I believe to be my invention, as well as numerous novel combinations and sub-combinations of parts which are to be found in the embodiments of the invention which are shown in the drawing, and hereinafter described and claimed.

In the drawing, Figure 1 is a central vertioal section of a carbureter embodying the invention. Fig. 2 is a transverse sectional view of the same in the plane indicated by line 22 on Fig. 1.. Fig. 3 is a central vertical sectional view of another embodiment of the invention; and Eiggl is a plan view thereof.

H In the carbureter shown in Figs. 1 and2, there is a mixing chamber A which may be means of a pipe 0 with the engine manifold. v Air be drawn into the mixing chamber on the induction strokes ofthe engine pistons through the open'tube B which passes through the fuel float cham- :ber F, and has'its upper end formed by the tubular stem 6 of the auxiliary air valve E WhiQh telescopes the upward prolongat on of said tube B. A fuel nozzle G is placed centrally within the air tube B, and is in communication with the fuel float chamber F. The auxiliary air valve lil consists of a tube (2 having at its upper end a laterally extended annular flange 6 which is adapted to seat itself on the margin of a circular hole a through the floor or bottom wall. a of the mixing chamber. the chamber 0 below the air valve through the screened openings 0.

H represents a fuel valve which is slidable through the upper wall or roof a of the mixing chamber. Its lower end is conical and is adapted to control the size of the.

fuel discharge orifice in the nozzle G. This valve H also passes loosely through and is guided by a boss 6? which is fixed to the auxiliary air valve. A coil spring J surrounds the fuel valve and is somewhat compressed between this boss (5 and a shoulder g on the fuel valve within the mixing chamber, whereby it applies to the air valve a yielding force tending to hold it closed, and applies to the fuel valve a force tending to open it. This spring should be of such tension and modulus that it will allow the auxiliary air Valve to be opened more or less by slight variations in the partial vacuum within the mixing chamber, so as to admit sufficient air to prevent any substantial increase of vacuum therein. As the air valve opens the spring J is put under increasing tension, and therefore applies an increasing force to the fuel valve tending tolift it,- and in fact sufficient to actually lift it. Bu this movement of the fuel valve from its seat, is opposed by the yielding resistant, shown in the form of a flat spring K which bears on the top of the valve. These two springs J and K must be so balanced, the one against the other that the spring move ment of the fuel valve which results from the increased tension of spring J as the air valve opens, will be such as to increase the fuel flow in proportion to the increase in the air flow.

Every engine will have its own individual characteristics, due to the number of cylinders, the absence of or presence in some degree of leakage, and other causes, which will call for different adjustments in the tension and modulus of the spring K. So also will different atmospheric conditions call for different adjustments of the tension and modulus of said spring. These adjustments are provided for by the construction shown; viz. the flat spring is fixed to a bracket N formed on the carbureter casing. rln arm M is adjustably fixed to said bracket; and in this arm is a set screw on, which bears on said spring K. By so moving this arm that the set screw is moved toward or from the free end of spring K, the modulus of the spring may be varied; and by screwing Air freely enters the screw m up or down the tension of the spring may be varied.

The carburetor shown in Figs. 3 and l differs from that which has been described somewhat in construction, but not in principle of operation, because the opening move- .monts of both the air valve and the fuel valve are produced by small 1ncreases 1n the vacuum in the carburetor. It has a mixing chamber A whose outlet may be connected by pipe C with the engine manifold. It has an air inlet tube B through its bottom, a fuel nozzle G arranged within this tube and connected with the fuel float chamber F. It has an auxiliary air valve E which, however, opens downward, but is normally held against its seat, so as to cover an opening through the top wall of the mixing chamber,

by a spring J. This spring is connected at its upper end with a lever It which is pivoted to a fixture. The opposite arm of this lever engages beneath a shoulder h on the fuel valve H, which valve is a rod passing down through a boss formed on the top wall of the mixing chamber, and having a conical lower end for closing to a greater or less extent the fuel discharge orifice in the nozzle. A flat spring K bears against the top of this fuel valve and normally overbalances the force of the spring J tending to lift the fuel valve from its seat; and the strength and modulus of this spring may be regulated by the adjustable bar l\/ and set screw m precisely as in the form of carbureter first described.

hen there is a suflicient increase of vacuum in the mixing chamber, produced, for example, by increasing the speed of the engine, this auxiliary air valve E will be opened to a greater or less extent, thereby putting the spring J under greater tension. When the air valve is moved a predetermined distance, the tension of the spring will overbalance the tension of the spring K and this fuel valve will be moved a little away from its seat, so as to properly enlarge the fuel discharge orifice in the noz zle. By thus utilizing the slight increase of vacuum to open the air valve so as to prevent any great increase of vacuum, and by utilizing the opening movement of the air valve to put under increased tension the spring which may open the fuel valve, and by opposing this opening of the fuel valve by a yielding resistant properly adjusted as to tension and modulus, the carbureter may be made to produce a uniform mixture under all conditions, and with a very slight increase in the vacuum required to induce a flow of fuel from the fuel nozzle.

Having thus described my invention, what mixing chamber having an air inlet,'a fuel nozzle for discharging fuel into said chamber, an air valve, a fuel valve, a spring which has the double function of opposing the opening of the air valve and of applying to the fuel valve'a force tending to open it, and a second spring which acts on the fuel valve only and opposes its opening movement, whereby the position of the fuel valve is determined by the balance. of tension of said two springs.

3. In a carbureter, the combination of a mixing chamber having an air inlet, a fuel nozzle for discharging fuel into said mixing chamber, avalve controlling the fuel discharge opening of said nozzle, a suction operated spring-controlled auxiliary air valve past which air may be drawn to the mixing chamber, means by which any increase in tension of the air valve spring due to this opening movement of said air valve will impart to the fuel controlling valve an increasing tendency to open, and an independent spring opposing the opening movement of the fuel valve.

4. In a carbureter, the combination of a fuel chamber, a mixing chamber having an air inlet, a fuel passage from the float chamber to the mixing chamber, a valve controlling the fuel opening, a suction operated spring-controlled air valve past which air may be drawn to the mixing chamber, means for causing the reduction in pressure in the mixing chamber to impart to the fuel valve an increasing tendency to open, and additional elastic means to oppose the opening movement of the fuel controlling mechanism. I

5. A carbureting device comprising a mixing chamber having an air inlet, a fuel inlet nozzle disposed within said air inlet, an auxiliary air valve controlling the admission of auxiliary air to the mixing cham- 6. A carburetor comprising a mixing.

chamber having an air inlet hole in its bottom, an air inlet tube which extends to withy in a short distance of said hole, a tubular auxiliary air valve which telescopes this tube and has an annular flange serving as a valve to close said hole, a fuel nozzle arranged in said air inlet tube, a fuel valve for varying the size of the discharge opening of said nozzle, which valve extends upward through a hole in the top wall of the mixing chamber, a coil spring embracing the valve and engaging a part of the auxiliary air valve and a shoulder on the fuel valve so as to exert a force tending to hold the former closed and to open the latter, and a spring engaging the projecting upper end of the fuel valve and opposing its upward motion.

7 In a carbureter, the combination of a fuel chamber, a mixing chamber having an air inlet, a fuel passage from the float chamber to the mixing chamber, a valve controlling the size of the fuel discharge opening, an auxiliary air valve adapted to be opened by an increase of vacuum in the mixing chamber, a spring which exerts its force on the auxiliary air valve resisting its opening movement and also exerting its force on the fuel valve in a direction tending to open it, spring opposing the opening movement of the fuel valve, and means for varying both the modulus and tension of the last mentioned spring.

8. In a carbureter, the combination of a mixing chamber having an air inlet, the fuel nozzle for discharging fuel into said chamber, a valve controlling the size of the fuel discharging opening of the nozzle, an air valve, and a spring which has the double function of opposing the opening of the air valve and of applying to the fuel valve a force tending to open it.

In testimony whereof, I hereunto aflix my signature in the presence of two witnesses.

ALANSON P. BRUSH.

Witnesses: V

E. L. THURSTON, H. R. SULLIVAN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

- Washington, D. 0. 

